The administration of 5 x 10 to the six mammary carcinoma tumor cells to strain 2 guinea pigs resulted in 100% tumor incidence regardless of the route of administration. Spontaneous metastases to the lungs were observed. The primary and pulmonary tumors were characterized as undifferentiated carcinomas. This tumor is weakly immunogenic following a challenge with 5 x 10 to the five viable tumor cells to animals previously exposed to irradiated cells alone or admixed with BCG. Development of monoclonal antibodies against the primary and pulmonary metastatic tumors is currently underway. Drug studies against a chronic myelogenous leukemia (CML) in strain 13 guinea pigs are ongoing. This leukemia follows a reproducible (although accelerated) course as observed in man, i.e., chronic phase followed by blast crisis, and death. Three clinically active drugs, busulfan, hydroxyurea or Cytoxan are currently being tested for their ability to extend the chronic phase and/or prevent the development of blast crisis. Development of monoclonal antibodies against the chronic and blast tumor cells is in progress. Monoclonal antibodies against each tumor will be examined alone, i.e., passive immunotherapy, or as carriers of drugs, toxins or isotopes for antitumor therapy.